Syntheses, X-ray crystal structures, and ligand substitution kinetics of the carbon-bonded chromium(III) complexes trans-(CrR(acac)/sub 2/(L)) (R = CH/sub 2/Cl, CHCl/sub 2/; L = H/sub 2/O, CH/sub 3/OH, pyridine)

Journal Article · Wed Jul 29 00:00:00 EDT 1987 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00262a039· OSTI ID:5522724

Ogino, H; Shoji, M; Abe, Y; Shimura, M; Shimoi, M

The alkylchromium(III) complexes trans-(CrR(acac)/sub 2/(H/sub 2/O)) (a) (R = CHCl/sub 2/, CH/sub 2/Cl; Hacac = 2,4-pentanedione) were prepared by the reaction of (CrR(H/sub 2/O)/sub 5/)/sup 2 +/ with Hacac and triethylamine. Synthetic methods reported previously for (CrR(H/sub 2/O)/sub 5/)/sup 2 +/ (R = CHCl/sub 2/, CH/sub 2/Cl) were improved to give approximately quantitative yields. The complexes trans-(CrR(acac)/sub 2/L) (L = CH/sub 3/OH, pyridine) were derived by replacing a coordinated water molecule in a with L. The X-ray crystal structure analyses of trans-(CrR(acac)/sub 2/(py)) (R = CHCl/sub 2/, CH/sub 2/Cl) have been performed. The carbon-bonded ligands CHCl/sub 2/ and CH/sub 2/Cl lengthen specifically the Cr-N bond trans to the Cr-C bond in trans-(Cr(CHCl/sub 2/)(acac)/sub 2/(py)) (b; Cr-N = 2.154 (7) A) as well as in trans-(Cr-(CH/sub 2/Cl)(acac)/sub 2/(py)) (c; Cr-N = 2.201(4) A). The elongation of the Cr-N bonds in b and c is reflected in substantial labilization of the ligand substitution reactions at the position trans to R: trans-(CrR(acac)/sub 2/(CH/sub 3/OH)) + L reversible trans-(CrR(acac)/sub 2/L) + CH/sub 3/OH. The rate constants (M/sup -1/ s/sup -1/) at 25 /sup 0/C in methanol for the formation of trans-(CrR(acac)/sub 2/L) are 85 +/- 2 (R = CHCl/sub 2/, L = py), 98 +/- 1 (R = CHCl/sub 2/, L = 4-methylpyridine), 57 +/- 1 (R = CHCl/sub 2/, L = isonicotinamide), and (1.2 +/- 0.5) x 10/sup 3/ (R = CH/sub 2/Cl, L = py), and the rate constants (s/sup -1/) for the backward reaction at 25 /sup 0/C are 15 +/- 1 (R = CHCl/sub 2/, L = py), 11 +/- 1 (R = CHCl/sub 2/, L = 4-methylpyridine), 33 +/- 1 (R = CHCl/sub 2/, L = isonicotinamide), and (5 +/- 2) x 10/sup 2/ (R = CH/sub 2/Cl, L = py).

• Research Organization: Tohoku Univ., Sendai, Japan
• OSTI ID: 5522724
• Journal Information: Inorg. Chem.; (United States), Vol. 26:15
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKANES
CHEMICAL PREPARATION
CHEMICAL REACTIONS
CRYSTAL STRUCTURE
CHROMIUM COMPLEXES
KETONES
PYRIDINES
CHEMICAL BONDS
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
LIGANDS
X-RAY DIFFRACTION
AZINES
COHERENT SCATTERING
COMPLEXES
DATA
DIFFRACTION
HETEROCYCLIC COMPOUNDS
HYDROCARBONS
INFORMATION
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
REACTION KINETICS
SCATTERING
SYNTHESIS
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties